Book excerpt: This practical book provides the detailed methodology and expert guidance required for measuring and manipulating cytosolic ion concentrations. In addition, the strengths, weaknesses, and pitfalls of various techniques are presented. It is an invaluable source for those needing an objective evaluation of current methodologies and for those contemplating setting up such procedures. - A one-source reference for measuring and manipulating intracellular ions and for comparing and evaluating current methodologies - Includes overviews of Optical probes and reagents - Fabrication and use of ion-selective microelectrodes - Use of NMR spectroscopy - Ionophores